Water Clarity: Watered down chocolate milk with a tough of foam.
Air Temp: @ 8:30 it was about 33 degrees (gloves were worn while on the sticks)
A buddy and I did a quick "scouting run" on the lower end of the flies-only section of the Pere Marquette. We dropped in at about 8:30 and were off the river by 11:30. While we didn't bring any fish to hand we turned nine browns. Most were in the 14-18" range the smallest being about 10", the largest about 20". We were using a variety of big streamers. Mad pups and larger leeches with a touch of flash seemed to be working the best.
My personal analysis was that it was too cold at night (down to 26) and the fish were just lethargic. Think about it like this. You don't want to get out of your sleeping bag (even to pee) when its cold outside. Why would they want to leave their confines. There is always tomorrow.